Stabilization of pleuromutilin derivatives against oxidation by sodium hypochlorite in aqueous solution

Abstract

A composition and method which provides a compound of the formula I: ##STR1## wherein either R 1 is ethyl or vinyl, n is an integer from 2 to 5 and each of R 2 and R 3 is alkyl of 1 to 10 carbon atoms. Also provided is a hypochlorite scavenger in solution with the formula I compound which stabilizes the compound against oxidation by sodium hypochlorite. A preferred solution contains the compound of formula I wherein R 1 is vinyl, R 2 and R 3 are ethyl as a salt of hydrogen fumarate i.e. tiamulin hydrogen fumarate. The solution is added to drinking water which is fed to farm animals as treatment for mycoplasma infection.

We claim: 
     
       1. A method of water treatment comprising providing an aqueous solution by providing water and adding to said water a hypochlorite scavenger and 0.0045 to 0.0125% (based on the weight of the aqueous solution) of a compound of the formula ##STR3## wherein either R 1  is ethyl or vinyl, n is an integer from 2 to 5 and each of R 2  and R 3  is an alkyl of 1 to 10 carbon atoms, and pharmaceutically acceptable salts of said compound, said hypochlorite scavenger being selected from the group consisting of sodium thiosulphate, acetone sodium bisulphite, ascorbic acid, dithiothreitol dithioerythritol, sodium sulphite, sodium nitrate, and urea, said compound being present in a weight ratio to the hypochlorite scavenger of from about 0.1:1 to about 500:1. 
     
     
       2. The method of claim 1 wherein said compound is tiamulin hydrogen fumarate. 
     
     
       3. The method of claim 1 wherein said hypochlorite scavenger is added in a first step and said tiamulin hydrogen fumarate is added in a second step. 
     
     
       4. The method of claim 3 further comprising adding lactose and wherein said lactose is 0.1 to 0.02% by weight of said aqueous solution. 
     
     
       5. The method of claim 1 wherein said scavenger concentration is above 40 ppm of said aqueous solution. 
     
     
       6. The method of claim 1 further comprising providing said aqueous solution to domestic animals as drinking water whereby mycoplasma infections are controlled prophylactically and therapeutically. 
     
     
       7. The method of claim 1 wherein said hypochlorite scavenger is added concurrently with said compound.